One of the goals of the recently collected international data such as English Longitudinal Study of Ageing EISA), Survey of Health, Ageing, and Retirement in Europe (SHARE), and Korean Longitudinal Study of Aging (KLoSA) that have been modeled after the Health and Retirement Study (HRS) is to allow for comparative international studies. Potential benefits of cross-national studies of aging are beginning to become widely recognized, and researchers have produced insightful findings from such studies. However, such studies are still small in number, and partly this is due to the fact that it is not straightforward to know which measures in the various surveys are fully similar and which are not. In this light, we aim at developing a resource that facilitates the use of different datasets in comparative studies, that is a repository of information, knowledge and experience, and which may serve as a library of survey questions for aging surveys. More specifically, our application has the following specific aims: (1) Create a digital library of survey questions used in all surveys that are incorporated in the system. (2) Develop a Google-like search facility that will allow researchers to search the digital library and put together analysis datasets with comparably defined variables. (3) Harmonize information about variable definitions and question formats across datasets, so that a researcher can easily see for each variable how it was measured and how that may differ across surveys. (4) Create a "Wikipedia-like" system, in which researchers can add procedures for the construction of derived variables, comment on problems in data, procedures followed by others, etc. (5) Enrich datasets with contextual variables, e.g. cost of living indexes for different countries, tax calculators, the cost of health care. (6) Include facilities to access and describe paradata. Paradata are 'external' data collected during an interview. (7) Make the products of the project available to the research community at large as a public good. (8) Expand the data library by adding emerging aging surveys, as they become available. [unreadable] [unreadable] [unreadable] [unreadable]